Posthole digger



2 SHEETS-SHEET l a; GE]

Nov. 11, 1952 e. A. ROBINSON POSTHOLE DIGGER Filed Sept. 19, 1950 Nov. 11, 1952 G. A. ROBINSON POSTHOLE DIGGER 2 SI'IEETS-Sl-IEET 2 Filed Sept. 19. 1950 Afro/r115) Patented Nov. 11, 1952 UNITED POSTHOLE BIGGER, George A. Robinson, Calgary, Alberta, Canada Application September 19, 1950, Serial No. 185,598 In Canada July 5, 1950.

4 Claims.

mounted at the head of the auger from a power take-off source of energy, and. the objects of the machine are to provide a unit of this nature which may be readily transported, is easy to operate, and with which holes to be dug may be quickly spotted on account of both the flexible joints at the shaft ends and the fact that this drive shaft is telescopic, with the advantage that holes-will be put down inexpensively when compared-with conventional types of such diggers.

A further object of importance is the-provision of manipulating handles incorporated in the head of the auger drive gear mechanism, which handles include means to quickly engage and disengage the drivable parts through a friction type cone clutch, thereby controlling the rota tion of the auger, and also by which the auger is guided for drilling in any desirable direction. A still further object is the PIOVlSiOIl'Df a special shaft bearing and casing associated with the auger manipulating handles, which due to its'pivotal connection therewith in a transverse manner to permit vertical planar movement only between the shaft and auger gear mechanism, apart from shaft rotation, prevents side twist between these parts due to possible excessive torque occurring in the auger spindle,'providing for safety in handling during drilling] Acutter blade is provided at the ground-engaging'end of the auger which is removably attached the'reto, and which blade is obliquely edged on two parallel sides so that it;i;may be reversed and also turned over as the edges Wear down during digging. This single bladei'is ad'- justably mounted on a bracket connected, indirectly to the auger spindle, and its radius for cutting operations may be adjusted within certain limitations depending on the dirt-raising capacity of the auger flights to the surface.

* With the exception of those parts specifically A further advantage in connection withthese invented parts is that the gears are in a'f'sealed oil bath enclosing case, and consequentlyf'wearing out of these parts is nearly negligiblef I With these objects and advantages in view this invention consists in the no'velfeatur'es of construction hereinafter described and claimed, and in the drawings accompanying this specification it must'be observed that similar numerals refer to similar parts through the several 'views thereof. I Fig.1 is a plan view of the auger handling member with covers of casings fragmented to show the internal elements, which are partly sectionalized. t Fig. 2 is a side elevational view of the handle assembly connected with the drive shaft and the driven auger spindle; V

Fig. 3 is a part sectionali zed view of the slip clutch assembly connecting the power take-off shaft collar with the telescopic shaft; .f

Fig-"4 is a view of the bit, bit holder shank and cutting blade, in elevation.

' Fig. 5 is a side view of Fig. 4. Fig. 6 is a section on line 6-6 in Fig. 4. Fig. 7 is an elevational view of the assembled digger. J j Referring to the drawings the numeral I 'signifies one of a pair of left and right side machinesupporting handle bars in parallel relationship, and connected together transversely by handles 2. A gear box 3 is supported between these side bars disposed nearer to one handle 2 than the other. This gear'boxencloses a set of ,bevel gears '4 for driving an auger 5 dependently. supported. therefrom, the hollow spindle 5a of which auger is carried by a shaft forming part-of the said gear assembly. A central drive" shaft 1 runs horizontally between and'parallel with the two side bars I and through thegear box 3, in. which box are bearJ ings 8 for the end of said shaft, and 9 toiin; termediate'ly journal the'shaft. Thisshaft exftends longitudinally between the side bars to carry the fixed member [0 of a cone clutch keyed to the shaft l.. The male part II of this clutch" bears slidably on the shaft 1, and isa rigid part of a universal joint assembly 12, which joint includes a ball l3 and cooperative spring [4, the

assembly being a thrust. bearing for theshaft l, The coupled member l2a of this universal joint connects with a drive shaft l5 of the telescopic power source Of a tractor.

purposed bearing I 5 integral with a, casing H, the latter enclosing the said universal joint, and is pivotally associated with and lies between the side bars I by means of studs l8. Studs lBa are threaded into the bars I and engage slots 18b in the sides of the casing [1. At this end of the hand-hold assembly adjacent the casing I! at sidebars l are bent upwardly. as at ,Ia .so that the :handle 2 at this end will conveniently bridge over the casing H.

A clutch operating handle 19 bridges over the gear box 3 being mounted pivotally on the side bars i by side rods 20. This handle isfiorcontrolling the operation of the clutch for starting or stopping the running of the gears and the auger. These rods 20 arebent at their bottom ends for their pivotal attachment to lugsLZl projecting downwardly from the side bars I by means of bolts 22, to swing radially thereabout,

theaxes of which bolts are the fulcrums for the .Io'ds 20, the elbow bend being'shown "at 23. At

each: of these "elbow bends is pivotallyattached a connectingrod' 24 by means-'ofapivot bolt "25 .for association with the clutch. 'Each 'said con- .necting rod is drilled'hollowrandthreadedatthe end opposite'to the 'pivot boltto receive a shackle bolt '26 for longitudinal screwable adjustment of the connecting ,rod. "The eyes "2:1:0f this shackle bolt are 'aifixed pivotally to -a cross "plate 28 'set transversely between'theside bars I which plate by the coactive relationshi of .the connectin rods 24, the rods 20 and the s1ideplate'28,;1 ref- .erably while "holding one or other of the :end

A slip clutch 'is introduced adjacent to the power take-01f source of power'shaft collar '32, andis connected directly to the flanged coupling '33 thereof by a friction assembly. This assembly consists of two flange plates, one of which 34 is attached by bolts '35 to the said flange coupling 33, and the other plate 36 faces against this one and with an angular friction plate 3.1 therebetween, the pie-tees "being keyed to a shaft 38. This shaft '38 is therefore driven by the power take-off shaft 32 through the slip clutch, and is connected to a telescopic shaft (Fig. 17),, at its end 38a,ifor driving the auger drive gears 4. .A spring 39 is'braced'between the plate 3.6 and a take-up nut 40 screwable on to a Ithreadedportion of the shaft 38 as at 4!. 3.111175 42 keep the nut 40 in place, and these nuts are so disposed for adjustment of the spring at suincient compression to maintain non-slip between plates 34 and 36 under normal working conditions of the auger. 7

Another feature of my invention is the bit for attachment to the ground-engaging end of the auger spindle. The auger spindle 5a being tublllar the shank. 43of this bit assembly is inserted therein, and a set screw 44 secures it. An enlarged portion 4'5 of the shank l3 acts as a shoulder for the auger stem. The bit member '46 is axis of the shank and the auger spindle. The

cutting edges of this bit member are shapedfor "to *presentaa :normal cutting angle-for the blade.

A slot 5| in the blade provides a means for .adjustment relative with the radius of the auger flights. The blade is so sharpened that it may be turned over, and its cuttin edges reversed as wear takes place, and it may be turned over endwise' to givefurther cutting advantages. The

ends of the blade are cut away as at 52 to fit the bbli'quely curved shape of the shank 45.

A cover plate 53 extends over the clutch from the top cover plate 54 of the gear. box 3, to which it is bolted. The gears 4 run in an oil bath in the'-'box"3,-and the auger stem 5 is journailled in a vertical bearing 55- depen'ding from thebox 3,

which bearing is of the thrust type. -A -"-thr-ust collar-'55 is affixed to the shaft 6 adjacen-tly be- "low this bearing-55, and is secured to the shaft by "a set screw 55a. 'Ih-is collar preventspossible jamming of the'gears-'4--due to auger thrust during digging operations.

'It should benoted that t-he pivotal action between the shaft 15 and this h-and hol'd assembly is in an upward and downward directi'ononthe trunnion studs 18 to accommodate the raising and lowering of the'auger. universal joint 51 which connects the shaft-5 8 a wit-lithe telescopic shaft 5 accommodates the free movement for spottingholelocations with the auger.

The importance of the journal l6 for the shaft 15 which is within the casing Flyishereemphasized, since this prevents any danger from the sudden turning of the 'handhold assembly about the auger axis, which might be'caused by additional torque occurring in the auger-"spindle.

What I claim and for whichidesireto 'sccure Letters Patent:

1. A (post hole digger assembly comprising a pair of elongated side bars disposed inspaced parallel relationship and joined at corresponding end portionsby a handleelement, a'gear housing A couple of lock rigidly carried betweensaid sidebars at end portions thereof remote from the first said end portions, driveand driven shafts :journa'led'in said gear box and'interconne'cted by gears, the driven shaft being rotatable about a vertical axis and adapted to be connected to an auger for driving the same, a bearing casing supported between said sidebars adjacent the'first said endpo'r'tion's and having a driving shaft rotatably carried thereby, said driving :and .drive shafts being "in'terconnected by first and second 'interengageable clutch members, means foreffecting interen'gagement of said clutch members, and a control handle carried by said side bars and pivotal about a horizontal axis and connected with said means for effecting operation thereof, said "handle element and control handle providing a pair of handles for manipulating'the auger wherebylifting of the assembly by said handles disengages said clutch members deactuating the auger, and lowering of the assemblyand manual pressure against the control handle effects inter-engagement of the clutch members for driving the auger.

2. The assembly of claim 1 wherein said driving shaft includes a pair of sections interconnected by a universal "coupling, one of said sections being rotatable with one of said clutch members, said bearing casing being pivotally carried by said side bars about an axis aligned with the pivotal axis of said universal coupling whereby lifting and lowering of the assembly relative to the source of rotative power can be accomplished.

3. The assembly of claim 1 wherein said means includes a plate longitudinally slidably carried by said side bars for effecting movement of one of said clutch members relative to the other of said clutch members.

4. The assembly of claim 1 wherein the first said end portions are upwardly bent so that said handle element overlies said bearing casing, the ends of said side bars remote from said bent end portions being joined by a handle element with said control handle in juxtaposition thereto,

6 whereby the juxtaposed handles can be manually squeezed together to effect tight frictional engagement between the clutch members for operating the auger.

GEORGE A. ROBINSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,515,441 Peterson Nov. 11, 1924 2,107,958 Pribyl Feb. 8, 1938 2,217,300 Templeton Oct. 8, 1940 2,533,123 Leavengood Dec. 5, 1950 2,533,957 Roelfs Dec. 12, 1950 

